Extraction of zinc, lead, and silver sulfids from their ores.



No. 735,071. v PATENTED AUG. 4, 1903.

G. D. DELP'RAT. EXTRACTION 0P ZINC, LEAD, AND SILVER SULFIDS FROM THEIRORE S.

APPLIGATION FILED JAN. 2. 1903.

H0 MODEL.

UNITED STATES Patented August 4, 1903.

" PATENT OFFICE.

GUILLAUME D. DELPRAT, OF BROKEN HILL, NEW SOUTH WALES,

AUSTRALIA.

EXTRACTION OF ZINC, LEAD, AND SILVER SULFlDS FROM THEIR ORES.

SPECIFICATION forming part Of Letters Patent NO. 7 3 5,071, dated August4, 1903.

Application filed January 2, 1903. Serial No. 137,586. (No specimens.)

T0 aZZ whom it may concern:

Be it known that I, GUILLAUME DANIEL DELPRAT, general manager of themines and works of the Broken Hill Proprietary Company, Limited, ofVictoria, a subject of the Queen of the Netherlands, residing at BrokenHill, in the State of New South Wales and Commonwealth of Australia,have invented new and useful Improvements in the Extraction of Zinc,Lead, and Silver Sulflds from Their Ores, of which the following is aspecification.

This invention relates to the extraction or concentration of sulfid oresto separate them from their gangue.

The ore is first finely ground or stamped and then immersed or droppedinto a bath or solution, hereinafter described. An apparatus forcarrying out the process forms the subject-matter of a separateapplication, filed March 9, 1903, Serial No. 146,895. This process isreadily carried out at ordinary temperatures and depends upon the oreparticles being attacked by the acid to form a gas. Each ore particle soattacked will have a bubble or bubbles of gas adhering to it, by meansof which it will be floated and can be skimmed or floated off thesolution. The particles of the gangue, such as silicates and othersubstances not quickly or readily attacked by acid or dilute acid, fallto the bottom of the body of the solution and are removed from time totime. To facilitatethe floating of the ore particles, suitable salts areadded to the solution to increase its speciflc gravity, as will behereinafter explained.

In extracting or concentrating, more especially the sulfld ores of zinc,lead, and silver, I make use of a nitric-acid solution, the gravity ofwhich is increased to one and fourtenths, (1.4,) more or less, by theaddition of a suitable nitrate, such as an alkaline-metal nitrate, asthe nitrate of soda, nitrate of potash, or another metallic nitrate, asthe nitrate of zinc dissolved in water, or a mixture of nitrates. Thesulflds in the ore are rapidly acted upon by the acid and gas-bubblesformed on them, that quickly carry them to the surface, whence they flowaway or are removed by skimming. The tailings or Waste may be removedfrom the bath from time to time, as is necessary or expedient.

The drawing shows in vertical longitudinal section the apparatus used.

Below an ordinary bin or hopper 1, having a regulating discharge-door 2,is the pan or vessel 3, having a sloping bottom 4. The liquor orchemical solution is supplied by pipe 5 from a suitable reservoir (notshown) at an upper level. Just below the door 2 is a plate 6 on pintlesor pivots 7 in slots 8, adapted to be clamped by set-screws 9 when theplate is adjusted to the required angle and with the required extent ofopening between the lower edge of said plate 6 and the bottom 4, thedirecting-plate being, primarily, to insure the total immersion of allparticles of ore in the fluid or liquor. At the lower end of theinclined bottom 4 is a tailings-receiver or sump 10, having atailings-discharge 11. At the receiving end of the sump 10 is abaffle-plate 12, extending close to the face of said bottom 4, theobject of which is to prevent accumulation of concentrates above thesump 10. Extending from the pan 3 is a launder or trough 13 to receivethe overflow and the concentrates. Under the bottom 4 is a piping 14,forming, with the air-inlet cook 15, a Bunsen burner for gas, so thatthe solution or liquor may be heated, if desired. The ore fed from thehopper 1 drops into the bath and slides by gravity over the bottom tothe sump, the ore particles being raised to the surface of the liquor bythe gas -bubbles formed, the action of the acid on these ore particlesduring their travel along the inclined bottom and ore floated OE Withthe overflow through the trough 13, or, if desired, skimmed 01?.

Having thus described my invention, what I claim as new therein, anddesire to secure by Letters Patent, is-

1. The method of separating ores from gangue, which consists in forminga bath containing nitric acid, feeding finely-ground ore thereto,whereby gas-bubbles will be formed on the ore particles to raise them tothe surface of the solution, and removing the particles of ore so liftedto the surface, substantially as described.

2. The method of separating ores from gangue, which consists in forminga bath containing nitric acid and a suitable nitrate, feedingfinely-ground ore thereto, whereby gas-bubbles will be formed on the oreparticles to lift them to the surface and removing the ore particles soraised, substantially as described.

3. The method of separating sulfid ores from their gangue, whichconsists in forming a bath containing nitric acid, increasing thegravity of the bath by adding thereto the nitrate of an alkaline metal,whereby gas bubbles will be formed on the ore particles to raise them tothe surface, and floating off the particles of ore so raised to thesurface, substantially as described.

4. The method of separating sulfid ores from their gangue, whichconsists in forming a bath containing nitric acid, adding thereto sodiumnitrate to increase the specific gravity of the bath, feeding thefinely-ground ore into 7 the bath, whereby gas-bubbles will be formed

